gotta quit with the ball motion study. LOL it doesn't say anything about polyester, reactive resin, or urethane (at least as far as what they are or how they react). In fact, it mentions them a total of three times (combined). The report is not a golden bullet.

urethane is a polyester compound - redwoodplastics.com/polyurethane among others.

from this site, referring to bowler's paradise:

Quote:

From bowlers paradise:Polyester/Plastic: The type of ball that most recreational bowlers will recognize is the polyester bowling ball, which is commonly referred to as a “plastic” bowling ball. Polyester bowling balls have been available since the 1960s. They have a low cost compared to the other types of bowling balls and they are very durable, which is why they are used as “house” balls on the racks of most bowling centers. The durability comes from the hard, low friction nature of the polyester cover. This low friction nature causes the “plastic” ball to skid more and maintain a straighter trajectory. “Plastic” balls are primarily used by beginning bowlers; however, many experienced and professional bowlers use them for spare shots and for very dry lane conditions.

Urethane: In the late 1970s, bowling manufacturers experimented with coverstocks softer than polyester in order to create more hook potential. The result of these experiments was a polyurethane coverstock, or urethane for short. Urethane has a higher friction surface than polyester, so it will hook more. It can be easily sanded or polished to control its hook potential. Urethane is the preferred coverstock for beginning hook bowlers. It is also the dry lane choice for many experienced bowlers.

Reactive Resin: In the early 1990s, ball manufacturer started adding resin particles to their urethane coverstocks. The resin made the ball tackier than plain urethane which increased its hook potential. A side effect of the resin is that it makes the ball hydroplane on the oil more than plain urethane. The combination of the increased skid on oil and stronger hooking ability on dry boards gives the resin ball a bigger backend reaction for more striking power than prior ball types. Reactive resin is the primary coverstock for most experienced bowlers on most lane conditions.

Particle: Experienced bowlers preferred the smooth reaction and controllability of urethane, but they could not refuse the power provided by reactive resin balls. The ball manufacturers response to this situation was to add textured particles such as ceramics and glass to the resin enhanced polyurethane balls. The added texture gave the ball more grip in the oil for a smooth, controllable hook style, while maintaining the powerful backend of reactive resin. The hook potential for most particle bowling balls is higher than all of the other types of coverstocks. This extremely high hook potential means that most particle balls are for use on oily lane conditions only. However, ball makers are constantly tinkering with the quantity and size of the particles used, so particle balls are becoming more versatile across many types of lane conditioning.

Another from TenPin (who called Motiv for info):

Quote:

My understanding (which included a phone call to Motiv asking this exact question) is that they are pretty much the same. As you said, reactive balls start with a urethane base and have various chemicals added to give them grip, oil absorption properties, etc.

from wikipedia:

Quote:

In the early 1990s, a new material known as "reactive resin" was introduced. Reactive resin is still made from polyurethane, but has been treated with additives while in a liquid state that create pores in the coverstock that allow it to absorb oil. As oil is absorbed into the ball rather than sitting on the surface, there is greater friction between the ball and the lane.

Let's assume you're correct. Would you answer some question that arise from my own experience which says urethane, never out-performs reactive resin under any circumstances except short oil on wood, or, if the bowler can generate 500 RPM's.

What's the difference between polyester and polyurethane?How do those additives affect friction?

Without dynamic weights;

What's the difference in the friction created between a polyester ball and a polyurethane ball?

What's the difference in the friction created between a polyurethane ball and a reactive resin ball?

If a urethane ball and a reactive resin ball are both thrown at the same speed in the same oil;

Which ball will create more friction? Which ball will begin to transition earlier?

If resin skids through oil, how come we don't see anyone throwing resin at 10 pins?

Finally, if you put the same weight block in a urethane ball and a reactive resin ball, then drill them identically, which ball will transition quicker?

Resin or reactive resin balls are polyester. Yes, they are plastic. As such, they DO slide more on oil, but react stronger when they hit the dry, at times transition angularly.

Urethane balls DO NOT slide as long as resin balls and react earlier (less slide), but more controllably on the dry.

So, in the 3 phases of a ball path, reactive resin will slide longer. The Urethane will hook earlier. And, the resin will roll more.

It is generally assumed, and may be proven, that the urethane transfers more energy to the pins and is more controllable, even in oil. I don't remember ever seeing a urethane banked of the dry or even roll out.

Yep, this is pretty much my personal experience.Urethane does skid of course, but it is a much shorter skid.Reactive skids way, way longer and this allows it to conserve more rotation so when it hits the dry it really takes off in a hurry!

By comparison urethane is getting earlier friction and by the time it hits the dry backend it is already rolling so it comes off very gently with nice control.

Here are two videos I took during the same session that illustrate the difference.

In the first video I am using my Rack Attack and you will see this ball gets really, really far up the lane before it even does anything.But once it does, it does it fast.Rack Attack:https://www.youtube.com/watch?v=o6HjsCC9p60

Now compare to this shot with my Karma urethane at 500 grit.The ball rolls out almost immediately! It is just too strong for the lane. I had to take it up to 2000 grit just to get some energy back.Karma Urethane:https://www.youtube.com/watch?v=eKyef2ZuF7Y

I don't disagree with the contention that urethane creates more friction than polyester.

I also don't disagree with the contention that urethane rolls early. A ball that begins to roll too early will ultimately straighten out and deflect in the pocket.

'CHAMP' stated "What makes reactive resin reactive is its ability to skid through oil." The whole purpose of the reactive-resin surface is to 'NOT' skid through oil.

What causes a reactive ball to skid is the weight block position, axis rotation, axis tilt and ball speed. Those items will also play a part in how any ball of any surface reacts. The more unstable a ball's weight block, the more the ball will skid.

Here's the caveat; The way a ball is drilled will not overpower the surface of the ball unless the ball is thrown so fast as to overpower both variables. Even with a 90 degree drilling angle, without sufficient speed, an aggressive ball will hook much earlier than a less aggressive cover-stock drilled the same.

If a person is throwing a reactive ball and because of oil, that ball recovers too late to carry, the adjustment is not to pull out a ball that creates less friction unless the bowler plans to move their feet right and point the ball right at the pocket.

If they did that with the reactive resin ball, it would recover too.

If we're talking about how each individual makes an adjustment that works for them, then ball surface is not a variable that needs to be discussed.

If we're talking about a person throwing reactive resin and urethane at the same speed, in the same spot, with the same axis rotation, tilt and speed, then reactive resin will always out-perform urethane.

Additionally, while all bowling balls may be plastic at some chemical level, Polyurethane is different than polyester. Reactive resin is different than polyurethane. A particle ball is different than a reactive resin ball.

The difference in surfaces are the height of peaks and distance between peaks. In the USBC BMS, these variables are referenced as Ra and Rs. Of the top 3 variables that cause ball motion, Ra and Rs are first and third.

The bottom line, the ball that creates the most friction is the ball that will also create the most ball motion, all other variables being equal.

anecdotal: Not necessarily true or reliable, because it's based on a personal account rather than facts or research.

My experience with urethane is the opposite of what yours is. I've used a Black hammer from the 80's, a Natural and a Super Natural. None of these balls gave me an advantage except when the lanes have broken down. On fresh oil, for me, urethane is useless.

Is what I've just said anecdotal or science?

Friction makes bowling balls hook. Any surface that creates more friction will create more motion assuming comparative balls are drilled the same and delivered the same.

The USBC Ball Motion Study has clearly shown that the properties of a bowling ball's cover-stock dominate the ball's movement characteristics on the lane.

Other variables believed by some in the bowling industry to have a significant effect on ball motion—such as static bowling ball drilling weights—were deemed insignificant in comparison.

Overall, the five factors that contribute most to ball motion were determined to be:

If we're talking about a person throwing reactive resin and urethane at the same speed, in the same spot, with the same axis rotation, tilt and speed, then reactive resin will always out-perform urethane.

And this is exactly what I had mentioned at the very beginning of this post and was the reason for my question.

Urethane out performed resin on the fresh.

My Dark Legend Solid would not hook, while my Crow would hook early and roll long and carry powerfully until it got oil soaked and then it lost its punch.

But then I was able to switch back to the Dark Legend and now it would carry because the Crow had taken enough oil off my target line so my resin ball could hook and carry.

This is the exact pattern that has occurred every week at the house I bowl at. So I now know I can bowl the first game with my strong urethane and break the lane down, so I can go to my reactive for the rest of the set.

You can dismiss this as anecdotal, but the reality remains and I have demonstrated a similar effect in the videos I posted.

So I think part of the problem is the definition of the word "perform" here.

For Nord, the way he's throwing it (and it's specifically to this), we need to define that first. Nord throws something of a full-roller, but it STARTS with a backward roll. Note that the finger grips (thanks for them being light! LOL) actually come BACK in the roll. (axis of rotation is about 5:00 as opposed to a more "typical" 8:00)

No matter the weight block (unless it's a ball), it is going to be more unstable, longer, than a "typical" shot where the ball starts more forward.

Also - Nord, you say that your urethane is sanded to 500. You don't mention what the rack-attack is, but box stock is 500/4000 pad. (EDIT - just noticed your video says box stock) So dull, but pretty high grit. And both are drilled differently (pin is located mid-grip on the rack (which is a lot more shiny) and at the thumb (very dull) on the urethane.

Now, look at his videos again - his ball IMMEDIATELY starts gripping and flares quickly around, but it has a long way to go to get around to a stable rotation. Yes, both balls have the same (or similar) cores, but their drillings are not the same, meaning they will take different times to get stable. So we enter a second variable in there. DOH!

Next, FROM THE VIDEO, Nord is throwing the urethane from two boards farther right, and utterly straight up the board. It looks like 7 on the urethane vs 9 on the rack attack.

Will two boards make a difference? Yes - at this point in a normal house pattern, yes, that's the difference between 125ul and 325ul (or whatever the units are, lol) - that's right on the typical house shot slope. (used http://peakbowl.com/LaneConditions for an easy to read graph - house shots won't be exactly the same, but it's typical).

So, for Nord, he's getting better performance from a ball that is more aggressive as it is thrown with a bit of backspin creating a lot of skid (because it has a long way to travel to flare to roll) and then has a sharper hook at the end . . .

vs.

a less aggressive ball with a more aggressive surface (I'm guessing - you don't say what the rack-attack's surface is) thrown two boards to the right, in the drier area, which grabs the lane earlier and thus flares more quickly and turns earlier and thus goes high.

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